How to forecast gust wind
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Hi, Thanks for your great work in creating Windy.
Recently I noticed the spatial pattern of gust wind is very similar to the wind forecast, the difference is only in the magnitude, like in the following figures. Is this the result of multiplying a factor? Or any other mechnism to forecast gust wind?
Hope for an answer sincerely.
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@artmunich
Is not a multiplying factor.
Wind gusts are computed by weather models
using an algorithm which takes into account
heating in boundary layer, stability conditions, orography, turbulence etc
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@Gkikas-LGPZ Thanks for your answer. Does this mean that you are post-process the model outcome and then show it in Windy? I guess neither ECMWF nor GFS would forecast gust wind.
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@Gkikas-LGPZ In this post(https://community.windy.com/topic/12/what-source-of-weather-data-windy-use), the model output is every three hours for the first 6 days. But isn't gust wind a short period phenomenon which only lasts for several minutes. So is the gust wind prediction a probabilistic one? Or by saying gust wind, it means the maximum wind speed? What's the time resolution of gust wind prediction?
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@artmunich
10m wind gust forecast is a meteorological parameter provided by the models.For ECMWF :
http://apps.ecmwf.int/codes/grib/param-db?id=49#grib2For GFS, parameter 180,
http://www.nco.ncep.noaa.gov/pmb/docs/on388/table2.htmlwindy just visualizes it.
For more details on ECMWF wind gust
https://confluence.ecmwf.int/display/UER/10+metre+wind+gust
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Thanks @Gkikas-LGPZ . I will summarize below in case of others have the same question:
In ECMWF model output, it's called 10fg(10fg1, 10fg3, 10fg6);
In GFS model, it's called GUST.
Gust is defined as the maximum 3 second wind at 10 m height as defined by WMO.
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@artmunich
To illustrate the fact that Gusts are not calculated from Wind by a multiplying factor, some examples here below show it clearly. On Mediterranean coasts the surrounding mountains give some very gusty local winds, for instance in the straight of Gibraltar:
Or, on east Greek coast, with summer north wind:
While in more normal conditions, Gusts do not exceed 10 kt compared to Wind:
In these 3 examples Wind and Gusts are taken exactly at the same place and with same Wind conditions (18 to 21 kt)
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@idefix37 Great, thanks!
At first I think at least there must be some gust factor, either a constant or a exponential formula. But now I realized that the gust is directly output from the model. That's even better!
